vscode-maven/Troubleshooting.md

Troubleshooting

Background knowledge

Where to find Error logs

There are 2 types of command execution methods.

• Background command. It spawns a child process in background for your command, and the process is showing in status bar. E.g. generating effective pom. When a background command fails, you will see an error toast along the lines of Background process terminated with code 1 or Error occured in background process. You can find error logs in an Output panel named Maven for Java.
• Terminal command. It sends plain text of your command to a terminal to execute. E.g. almost all the other Maven commands. Error logs are directly printed in the corresponding terminals.

Requirements

• Install Java. Java Runtime is essential to run Maven commands. E.g. AdoptOpenJDK, Oracle OpenJDK, etc.
• Install Maven / Maven Wrapper. The extension actually leverages Maven executable file in your local machine. By default, it tries the following ones in order:
  1. The absolute path specified in config maven.executable.path if it is not empty. This should be the full path including mvn, e.g. "maven.executable.path": "/opt/apache-maven-3.6.2/bin/mvn" in your settings.json file.
  2. mvnw file under your workspace root folder. (If you prefer to bypass this one, you can change value of config maven.executable.preferMavenWrapper to false.)
  3. mvn in your system's PATH.

Possible error messages

Error message can be collected either directly from the integrated terminal, or from Maven for Java output panel.

• Maven executable file not found/set.

  Command failed: mvn --version 'mvn' is not recognized as an internal or external command, operable program or batch file.
  

  In this case, please follow above instructions to set available Maven executable path.

• M2_HOME not correctly set.

  Error: Command failed: mvn help:effective-pom -f "xxxxxxxxxxxx\pom.xml" -Doutput="xxxxxxxxxxxxxxx\effective-pom.xml"
  Error: M2_HOME is set to an invalid directory. 
  M2_HOME = "xxxxxxxxx\apache-maven-3.3.9\bin" 
  Please set the M2_HOME variable in your environment to match the 
  location of the Maven installation
  

  In this case, please follow the error message to reset a correct M2_HOME.

• JAVA_HOME not correctly set.

  The JAVA_HOME environment variable is not defined correctly
  This environment variable is needed to run this program
  NB: JAVA_HOME should point to a JDK not a JRE
  

  In this case, please specify a correct JAVA_HOME environment variable, or re-install JRE/JDK if necessary.